5 facts about razor-sharp teeth in 'Shark Week'

SUMMARY: Did you know that sharks can detach their upper jaw when devouring prey?

If you couldn't get enough of Discovery Channel's "Shark Week," you're not alone. On average, about 2.2 million people tune into the nonstop prey-devouring, teeth-sinking fun each year. But our fascination with the ocean's top predator doesn't have to end with "Shark Week." Let's take a look at five fun facts about shark teeth:

1. Sharks sport thousands of teeth
At any given time, great white sharks have about 150 teeth in seven rows. But over their life spans, sharks shed up to 20,000 pearly whites. They also have hundreds of teeth beneath the gums that are ready to move into place whenever their teeth break off. Imagine if sharks had a tooth fairy - they'd be swimming in dough!

2. Shark teeth have built-in toothpaste
The surface of a shark's tooth is made up of 100 percent fluoride, the active ingredient in most toothpaste and alcohol-free mouthwashes. These predators would never have to get cavity treatments by dentists since they never develop dental caries, according to the Discovery Channel. Meanwhile, the teeth of humans and other mammals contains hydroxyapatite, an inorganic constituent also found in bone.

3. They are born with teeth
Our teeth first develop in the gums before birth and start erupting at about 6 months of age. Shark pups, on the other hand, are born with a full set of teeth so that they can feed and fend for themselves right out of the womb, since parental care and protection is not part of the species' development.

4. Sharks have different types of teeth
Similar to our incisors and molars, sharks have a different types of teeth. Some are sharp and thin while others are flat for crushing shellfish. What's more, each type of shark has a different shaped tooth depending on their diet. Goblin and sand tiger sharks have very long, thin teeth suited for catching small fish, while the great white has serrated teeth to cut easily through flesh and bone.

5. A shark bites with upper and bottom jaws
Most animals only use the bottom jaw to chew because their lower jaw moves freely while the upper jaw is firmly attached to the skull. However, sharks have a very unique jaw structure where the upper jaw rests below the skull but can detach when the animal attacks its prey. This lets the shark thrust its entire mouth forward to snatch its food.